A common means to determine the location of a device is to use a satellite position system (SPS), such as the well-known Global Positioning Satellite (GPS) system or Global Navigation Satellite System (GNSS), which employ a number of satellites that are in orbit around the Earth. Position measurements using SPS are based on measurements of propagation delay times of SPS signals broadcast from a number of orbiting satellites to an SPS receiver. Once the SPS receiver has measured the signal propagation delays for each satellite, the range to each satellite can be determined and precise navigation information including 3-dimensional position, velocity and time of day of the SPS receiver can then be determined using the measured ranges and the known locations of the satellites.
Knowledge of the location of a device has many uses, one of which is known as augmented reality. Augmented reality combines real-world imagery with computer generated data, such as graphics or textual information. Augmented reality may be useful for activities such as navigation or simply orientating oneself within an environment.
One of the first and most difficult steps in navigation and information discovery is physically orienting oneself in the correct direction. In order to make use of data in augmented reality, the user generally needs to find and face the target item with the camera. For data or links, the target item is not visible unless the camera is facing the correct direction. For navigation, incorrect orientation results in the user initiating navigation in the wrong direction.
Current augmented reality methods for directing the user to turn to face the target item include the use of directional elements such as arrows. For example, augmented reality systems may use two or three dimensional arrows in the center or edge of the user's view, indicating rotate left or right. Another directional element that is currently used is a top view radar type display that indicates the relative distance and direction to target items.
Current methods of providing orientation information have several problems, however. For example, directional arrows do not provide information with respect to how far one should turn to face the target element. Accordingly, it is difficult to tell how far to turn. Moreover, if the user turns quickly, there is no indication when to slow down so as not to over shoot the desired target item or direction. Further, the use of top view radar displays is distracting as users find it difficult to interpret or determine its relevance and to relate the top view to the user's actual surroundings. When used for navigation, current orientation methods give the user a sense of urgency to orient themselves to the target item causing the user to engage in potentially dangerous behavior, e.g., not facing the direction of travel.